Less diarrhoea and bioequivalence with the new nelfinavir 625mg tablet

Stephen Taylor, for HIV i-Base

Sticking to the NFV and diarrhoea theme, several presentations addressed the pharmacokinetics and bioequivalence of the new formulation NFV 625 mg tablet.

These tablets contain the same amount of NFV but the excipient carrier compounds have been entirely changed in the new formulation, a move that may improve tolerability. In summary, when the 625mg was dosed as two tablets BD it showed almost identical PK parameters to five of the traditional 250mg tablets BD [1, 2, 3].

For those with a scatological sense of humour, the presentation by Margaret Johnson from the Royal Free Hospital in London was listened to with great interest. Patients were issued with “stool diaries” and completed these on a daily basis using the “Bristol stool and urgency algorithms”. On a more serious note, in this switch study, from old to new, the number of diarrhoea events of grade three or four severities reduced significantly upon changing to the new formulation.

It is likely that this new formulation tablet will be welcomed by all those currently taking the old formulation NFV tablets, as it will reduce pill burden and should improve tolerability. Whether it will increase the number of new patients starting NFV as a single protease inhibitor remains to be seen. After this meeting some pharmacologists may suggest that a higher dose of NFV than is currently marketed maybe more virologically effective while not increasing side effects.

Submission of the new formulation to the European Medicines Evaluation Agency is set for May this year.


  1. Kaeser B, Akintola DJ, Saifulanwar A et al. Improved gastrointestinal (GI) tolerability of Roche nelfinavir 625 mg film-coated tablets in comparison with nelfinavir 250mg film-coated tablets (Viracept) Abs 41 : P 6.4
  2. Charcoin JE, Oxley P, Gerber G et al. Pharmacokinetics of Roche nelfinavir 625mg film-coated tablets and nelfinavir 250mg tablets (Viracept) are comparable. Abs 42 : P 6.5
  3. Nieto-Cisneros L, Johnson M, Horban A et al. Investigation of the gastrointestinal tolerability and pharmacokinetics of the Roche nelfinavir 625mg film-coated tablets in comparison with nelfinavir 250mg film-coated tablets (Viracept) in HIV patients Abs 43 : P 6.6

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